Ring systems from azo dyes



Patented July 18, 195Ci RING SYSTEMS FROM AZO DYES Jack F. Morgan, Delmar, N. 155., and Harry W.

Grimmel, Providence, R. I., assignors to General Aniline & Film Corporation, New York.

N. Y., a corporation of Delaware, 1

I No Drawing.

:This invention-relates to novel polynuclear Nwheterocyclic compounds and to a process for preparing them. a

. .In accordance with this invention, novel heteroev cyclic compounds of the class consisting of na hg the [2,1 e1 tetrazolo [5,1 cl as triazines. and: Mnaphtho: [2,1-e] -s-triazolo- [5,1-el -as-triazines, having the following nuclear structurez;

wherein X represents 'tetravalent carbon or tri valentnitrogen, are obtained by coupling a compound'of the class consisting of diazotized 5-ami-' notetrazole. and diazotized 5-amino-s-triazoles (i. a, 5-amino-1,2,4-triazoles) with a B-naphthylamine compound susceptible to coupling in the alpha-position ortho to the, B-amino group; and effecting ring. closure of the resulting azo compound by elimination of the fi-amino group and a hydrogen'atom (formingammonia or an amine) The polynuclear N-heterocyclic compounds thus obtained are valuable intermediates for organic syntheses; particularly for the synthesis of organic dyeing properties.

dyestufls. Some of the products themselves have" "fl-naphthylamine compounds suitable for preparing the azo compounds employed as intermediates' forthe products of this invention include fi-naphthylamine, N-monalkyl-p-naphthyb which the first two may occupy any nuclear positionother than the alpha-position ortho to the B-amino group, while the sulfo and carboxy: groups may occupy any nuclear position. except.

thetwo positions ortho to the p-amino group (since the presenceof anv acidic substituentlin,

B -position of a 2-naphthylamine prevents ring closure). fl-naphthylamine compoundsucontainef ing a nuclear hydroxyl group aregenerally um I suitabIesincethe hydroxyl group usually acti-* Application se ptember 21, 1948,

Serial No; 50,444

vates -a second nuclear position for coupling, and thus interferes with coupling of the diazotized amino triazole or tetrazole exclusively in the alpha-position ortho to the B-amino group.

5-amino-s-triazole compounds serving as starting materials in preparing the aforesaid azo intermediates for the products of this invention include unsubstituted S-amino-s-triazole and nuclear substitution products thereof containing substituents such as an alkyl group (e. g., a methyl or ethyl group) or a carboxy group in the 3-position. V v

-.In preparing the intermediate azo compounds, 5-aminotetrazole or the 5- amino-s-triazole compound is diazotized in the usual manner by treatment with nitrous acid at low temperature, and

the resultingdiazo compound is coupled in acid medium with a p-naphthylamine compound of the class specified above. The resulting azo compound is then subjected to ring closing treatment,'adaptedto'eliminate the ,B-amino group of l the naphthylamine compound. For this purpose,

the'azo compound is preferably heated in an aqueous'solution ofstrong mineral acid such as sulfuric'acid or hydrochloric acid. The fi-aminogroup'is eliminated with formation of an ammonium or alkylamine' salt. The resulting polynuclear N-heterocyclic compound is separated fromzthe'reaction mixture, e. g., by salting out, if necessary, and filtration. The crude product can be purified-by the usual methods ordinarily involving recrystallization from a suitable solvent.

Therpreparation of compounds within the purview ofthis invention is illustrated by the followingexamples.

anhydrous sodium carbonate dissolved therein, adding 2l g."of sodium nitrite in 30% aqueous solution, and slowly adding the resulting solution to anagitated mixture of 450 cc. of water, 450 g. of ice and cc. of concentrated hydrochloric acid, while-maintaining the temperature at or below 0? C. After 15 minutes, the resulting solution of diazotized 5-aminotetrazole was added to anagitated solution of 43' g. r ofp-naphthylamine filter cake was added to a solution of 250 cc. of concentrated sulfuric acid in 2000 cc. of water, and the resulting mixture was heated at 90 to 100 C., while agitating, for 1 to 3 hours. The color of the suspended solids in the reaction mixture changed during this treatment from red to yellow. The reaction mixture was then filtered, and the filter cake washed with water and dried. The crude product thus obtained amounted to 50 g. or 75% of theory. Upon crystallization of the product from dioxane, a pale yellow crystalline material was recovered, having the following, analysis:

-' Calculated Found" Per can! corresponding to the empirical formulaCirHaNu. The reaction occurring in the foregoing ring closure. treatment can be: formulated-asfOHQ SJ The resulting product is thus naphtho- [El-e11 tetrazo1o-[5,1-cl -as-triazine.

Example 2 12.8 g. of S-amino-1,2,4: triazole-3 -carboxylic acid were dissolved by warming. in a mixture of 50 cc. of concentrated hydrochloric acidand- 100 cc. of water. The solution wascooled, to --5 C. and 7 g. of sodium nitrite in: 30% aqueous 50111-- tion were added while maintaining;the :temperature below 0 C. The resulting-slurry was added to an agitated solutiongof 14.3 g. ofip-naphthylr:

aminein a mixture of 15-00; of concentrated Ely-- drochloric acid and 1000 cc. of water... stirring for 15 minutes, a redslurry \tlasobtairied', to which 75 cc. of concentratedhydrochloric-acid were added. The-mixture was heatedat-boili'ng temperature for 2 to 3-hours,--and'filter-ed. Theresulting insoluble light tan coloredproduct was light yellow crystalline solid, and was found: to.

have the following composition upon analysis:

After:

corresponding to the empirical formula C12H'1O2N5 The reaction occurring in the ring closing treatment of this example may be formulated as follows:

NH- N H:

HCl

COOH

Example 3 A solution of 22.3 g. of 2-naphthylamine-6- sulfonic acid and 5 g; of sodium hydroxide in 500 cc. of water was acidified by adding thereto 12 cc. of glacial acetic acid. 8.5 g. of 5-aminotetrazole were diazotized by the procedure outlinedin Example 1,. and added to. the acidified. solution of" 2-naphthylamine-6 sulfonic acid. After stirring for 30 minutes, tocomplete the.

coupling] reaction, 50 cc. of concentratedsulfuric? acid were added, and the resultingreddish orange slurry was heated at 90 C. for 1 hour. A' greenish yellow solution was obtained which. was. partially. neutralized'by adding. 60 g. of sodium hydroxide. in the formof a, 30% aqueous solution, and; then treatedwith 200g. ofsodium sulfate.v Thecrude;

light yellow product'which separated from the.

solution was'isolatedlby filtration. Topurify. the.

water made slightly alkaline with. sodium bi carbonate. The solution was treatedwithcharcoal filtered and gradually cooledl. Thepurified sodium salt. of." the. product crystallized. from the. solution in. the form. of? light yellow crystals, having the following structure:

The product is thus 6 su1fo naphtho [2;I-el tetrazolo-lil-cl -as-triazine. Analysis of the: pro'duct.-yielded-' the following results. I

Calculated Found "Calculated Found 0 --per-cent- 58.-86"- 5 59.0-1- P 5 N -per;cent 26. 41. 26.165} N M 91 Per 25 8 Neutralization Equlvalent 265. 2. 262.4 S 9.83, 9:81;.

the 3-methyl'= It was found that-the product possessed aflinity for wool in dyeing treatments.

Corresponding 6 sulfo naphtho-s-triazolo astriazine compounds are obtained, as illustrated in Example 2, upon using 5-amino-1,2,4-triazole or its 3-carboxy'or 3-methyl-derivative instead of 5- aminotetrazoleas the starting material in the foregoing example.

Other p-naphthylan ine compounds which can be substituted for" the" B-naphthylami'ne or 2- naphthylamine-B-sulfonic acid of the foregoing examples, include the following:

2-naphthylamine-4-sulfonic acid 2-naphthylamine-5-sulfonic acid Z-naphthylamine-G-sulfonic acid 2-naphthylamine-7-sulfonic acid 2-naphthylamine-8-sulfonic acid 2-naphthylamine-4,8-disulfonic acid 2-naphthylamine-5,7-disu1fonic acid 2-naphthylamine-6,8-disulfonic acid 2-naphthylamine-4,6,8-trisulfonic acid 5-nitro-2-naphthylamine 8-nitro-2-naphthylamine 4-bromo-2-naphthylamine 'I-aminu-Z-naphthoic acid N-methyl-Z-naphthylamine N-ethyl-Z-naphthylamine When N-alkyl (e. g., N-methyl or N-ethyl) ,B-naphthylamines are used, the ring closure occurs in the same manner as illustrated in the examples, except that an alkyl amine salt is formed as the by-product instead of an ammonium salt.

As indicated in the examples and the foregoing table, p-naphthylamine compounds which are suitable as starting materials have the alphaposition ortho to the p-amino group unoccupied to permit coupling in this position with the diazotized amino-triazole or -tetrazole. Neutral substituents such as nitro groups or halogens (e. g., chlorine or bromine) can occupy any of the other nuclear positions, while acid substituents such as carboxy or sulfo groups can occupy any position other than the two positions ortho to the p-amino group. It has been found that an acid group (sulfo or carboxy) in the 3-position of a 2-naphthylamine interferes with elimination of the Z-amino group required for ring closure, possibly by reason of the formation of an inner salt of the amino group.

Hydroxyl groups are not included as nuclear substituents of suitable B-naphthylamines, since they generally interfere with coupling of the diazo compound exclusively in the alpha-position ortho to the fl-amino group. I-Iydroxyl groups can be introduced into the naphthalene nucleus of the final product, however, by conventional methods, such as reduction of a nitro group to an amino group, diazotization, and hydrolysis of the diazonium compound.

In carrying out the ring closure of this invention, a strong acid, preferably a mineral acid such as hydrochloric or sulfuric acid is used, in an amount corresponding to at least one equivalent per mol of azo compound. The reaction is accelerated by the presence of excess acid and accordingly, an excess is preferably used. While heating at lower temperatures is eifective for causing ring closure, temperatures from 90 to 100 C. are preferred to insure a more rapid reaction. It has been shown experimentally that one mol of ammonia or alkylamine is eliminated for each mol of azo compound, thus providin N N N v wherein X represents a member of the group consisting of trivalent nitrogen and tetravalent carbon.

2. Naphtho [2,l-e] tetrazolo-[5,l-cl-as-triazine, having the following formula:

3. Naphtho [2,1-e] 3 carboxy-s-triazolo- [5,1-c] -as-triazine, having the following formula:

4. 6-sulfo-naphtho-[2,1-el tetraz0lo-[5,l-c]- as-triazine, having the following formula:

N N Ll 5. A process for preparing a heterocycllc compound of the class consisting of naphtho-[2,l-e]- s-triazolo-[5,1-cl-as-triazines and naphtho- [2,1-el-tetrazolo-[5,l-cl as triazines which comprises heating a compound of the class consisting of tetrazoleand s-triazole-[5-azo-1lnaphthyl-Z-amines and -2-monoalkylamines in. acid medium to effect ring closure by elimination of the 2-amino group and a hydrogen atom.

6. A process for preparing a heterocyclic compound of the class consisting of naphtha-[2,l-els-triazolo-[5,1-cl-as-triazines and naphtho- [2,1-e] -tetrazolo-[5,1-cl as triazines which comprises heating a compound of the class consisting of tetrazoleand s-triazole-[5-azo-1lnaphthyl-2-amines and -2-monoalkylamines in an aqueous solution of a strong acid.

'7. A process for preparing naphtha-[2,1-eltetrazolo-[5,1-cl-as-triazine which comprises heating tetrazole-[5-azo-ll-naphthylamine-2 in an aqueous solution of a strong mineral acid, to effect ring closure with formation of an arm monium salt of the acid.

.8.; A process for preparing naphtha-[2,1-e1-3- mineral acid, toefiectring closure withformation carboxy-s-triazolod5,1-c] as triazine which of an ammonium salt; of the 'acid'. v comprises :heating B-carboxy-s-triazolo-[5-azo- JACK F; MORGAN. LI-naphthylamine-Z in the aqueous solution of a HARRY W. GRIMMEL. stronglm'ineral acid, .to effect ring closure with 5, 1 formation of an ammoniumusalt of the acid. REFERENCES CITED A process for Preparing fi-sulfo-n'aphtho- The following references are of record in: the

-L2,,1 teJS-tetrazolo-[Bflw]-as-triazine which comfile of th t prises. heating tetrazo1e-E5-azo-1]-6-su1fo-naphthyIam'ineT-Z inan: aqueous solution of a strong 0 fur Prat page 197 

1. A POLYNUCLEAR HETEROCYCLIC COMPOUND OF THE CLASS CONSISTING OF NAPHTHO-(2,1-E)-S-TRIAZOLO(5,1-C)-AS-TRIAZINES, AND NAPHTHO-(2,1-E)-TETRAZOLO-(5,1-C)-AS-TRIAZINES, OF WHICH THE NUCLEUS HAS THE FOLLOWING STRUCTURE: 